Prime minister Boris Johnson on Sunday (3) warned that the current tiered system of lockdown to arrest the spread of COVID-19 may have to be toughened further as the UK grapples with the new strain of the coronavirus.

As teachers’ unions have been calling for a countrywide closure of all schools for a few weeks due to the rapid spread of the new variation, Johnson insisted that parents should send their children to school from Monday in the areas where they remain open as the threat to young kids from the deadly virus is “very small”.

However, he admitted that even stricter restrictions for the wider public may be on their way in the coming weeks as the coronavirus cases in the country jumped by 57,725 this weekend, taking the death toll close to 75,000.

“Alas, restrictions may be about to get tougher,” Johnson told the BBC, when asked about the lockdown.

“It may be that we need to do things in the next few weeks that may be tougher. I’m fully reconciled to that. I think the whole country is fully reconciled to that. There are a range of tougher measures that we might have to take.

“Schools are safe. It’s very important to stress that. The threat to young people, kids, is very small. The risk to staff is very small. The benefits of education are so huge,” the prime minister said.

Under the current rules, most of the country is under the toughest measures already with Tier 4, which involves a near-complete shutdown of most businesses and non-essential retail as the state-funded National Health Service (NHS) comes under an increasing pressure with the mounting rate of hospitalisations.

Defending his handling of the pandemic, Johnson, a COVID-19 survivor, said that his government had taken “every reasonable step that we reasonably could” to prepare for winter months.

It comes as the NHS prepares to begin rolling out the Oxford University vaccine produced by AstraZeneca from Monday, as hospitals began receiving deliveries of the jabs this weekend after it became the second vaccine to be given regulatory approval after the Pfizer/BioNTech vaccine against COVID-19.

Johnson said that there will be “around 530,000” doses of the new vaccine available from next week.

“We’re rolling them out as fast as we can,” he said, when asked about the numbers of both vaccines being pumped into the health service network.

“We know there are challenges still ahead of us over the coming weeks and months, but I’m confident this is the year we will defeat coronavirus and start building back better,” he said.

Hundreds of new vaccination sites are due to be up and running from next week as the NHS ramps up its coronavirus immunisation programme with the newly-approved vaccine.

“The delivery of the Oxford AstraZeneca vaccine marks another first for the NHS, and a major milestone in humanity’s battle against coronavirus,” said NHS chief executive Sir Simon Stevens.

“The vaccination programme – the biggest in NHS history – has got off to a strong start, and by New Year’s Day we’d been able to vaccinate more people than the rest of Europe combined.

“Now we have a second, more versatile jab in our armoury, and NHS staff are expanding the programme as extra vaccine supplies come onstream. The arrival of the Oxford jab, coupled with more Pfizer vaccine being made available, will allow us to protect many more people faster,” he said.

Second doses of either vaccine will now take place within 12 weeks rather than the 21 days initially planned with the Pfizer/BioNTech jab following a change in guidance which aims to accelerate immunisation.

This new guidance has proved controversial because initially priority patients were urged to remember to go for their second dose after 21 days.

But medical chiefs have defended the change, saying it means more people should get a first dose before the initial group gets their second, which would result in longer term protection against the deadly virus.

In March, Johnson was tested positive for the coronavirus and was admitted to hospital and spent three nights in intensive care.